Programmable implant having an angled exterior surface

ABSTRACT

Various embodiments of implant systems and related apparatus, and methods of operating the same are described herein. In various embodiments, an implant for interfacing with a bone structure includes a web structure, including a space truss, configured to interface with human bone tissue. The space truss includes two or more planar truss units having a plurality of struts joined at nodes. Implants are optimized for the expected stress applied at the bone structure site.

PRIORITY CLAIM

This application is a continuation application of U.S. patentapplication Ser. No. 14/036,974 filed on Sep. 25, 2013 which claims thebenefit of U.S. Provisional Application No. 61/705,403 filed on Sep. 25,2012 and U.S. Provisional Application No. 61/801,597 filed on Mar. 15,2013.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to medical devices and, morespecifically, to implants.

2. Description of the Relevant Art

Implants may be used in human and/or animals to support and/or secureone or more bones. For example, implants may be used in the spine tosupport and/or replace damaged tissue between the vertebrae in thespine. Once implanted between two vertebrae, the implant may providesupport between the two vertebrae and bone growth may take place aroundand through the implant to at least partially fuse the two vertebrae forlong-term support. Implants may include relatively large rims with solidmaterial that may cover, for example, 50% of the area that interactswith the endplate. The rim may provide a contact area between theimplant and the vertebral endplates. Large rims may have severaldrawbacks. For example, large rims may impede bone growth and reduce thesize of the bone column fusing the superior and inferior vertebralbodies. Additionally, large rims preferentially support and regionalizeloads, preventing distribution of force and accommodating response. Theprocess of localizing loading also serves to under load other areas ofthe vertebral bodies, thereby activating regional resorption accordingto negative microstrain.

Spinal implants may include open channels through the center of thesupporting rims in a superior/inferior direction. The open channeldesign may require members of the implant that separate the rims thatinteract with the vertebral endplates to absorb the compressive forcesbetween the vertebral endplates. This may increase the pressure onsmaller areas of the vertebral endplates and may potentially lead tostress risers in the vertebral endplates. Further, while bone graftmaterial is often used in conjunction with implants to encourage bonegrowth, the open column design of implants may reduce the likelihood ofbone graft material from securing itself to the implant which couldresult in a bio-mechanical cooperation that is not conducive topromoting good fusion.

Bone graft material may be packed into the implant in a high-pressurestate to prevent bone graft material from exiting the implant whilebeing placed between the vertebral endplates. The high-pressure statemay also reduce the potential for the bone graft material loosening dueto motion between the implant and the vertebral endplates or compressiveforces experienced during settling of the implant. In addition, ahigh-pressure environment may allow the bone graft material to re-modeland fuse at greater strength. High-pressure states, however, may bedifficult to create and maintain for the bone graft material in animplant. In particular, the lack of attachment of the bulk graft cannotfully accept or integrate the differential loading anticipated in normalkinetic scope.

Various embodiments of implant systems and related apparatus, andmethods of operating the same are described herein. In variousembodiments, an implant for interfacing with a bone structure includes aweb structure, including a space truss, configured to interface withhuman bone tissue, including cells, matrix, and ionic milieu. The spacetruss includes two or more planar truss units having a plurality ofstruts joined at nodes.

In an embodiment, an implant for interfacing with a bone structureincludes: a web structure that is formed from a plurality of strutsjoined at nodes, wherein the web structure is configured to interfacewith human bone tissue. The diameter and/or length of the struts and/orthe density of the web structure are predetermined such that when theweb structure is in contact with the bone structure, its matrix, or thecells from which it is derived, at least a portion of the struts createa microstrain, that is transferred to the adherent osteoblasts, bonematrix, or lamellar tissue, of between about 1με and about 5000με, orbetween about 500με and 2000με, or between about 1000με and about 1500μεor to a negative reflection of compression in interval and resonancewith loading in both flexion, extension, torque, or combinationsthereof. These ranges are optimized to known load-response dynamics, butare meant as guides rather than limitations to the activity andresponse. The diameter and/or length of the struts is predetermined sothat at least a portion of the struts during loading create a change inlength of the adherent osteoblasts, bone matrix, or lamellar tissue, ofbetween about 0.05% and about 0.2% or between about 0.1% and about 0.15%causing an osteogenic response. Struts may have a length of betweenabout 1 mm to about 100 mm. The diameter of the strut may bepredetermined such that the struts create a change in length of theadhered osteoblasts of between about 0.05% and 0.2% when the webstructure is in contact with the bone structure. Alternatively, thediameter of the strut is predetermined such that the strut undergoes achange of length of between about 0.000125% and 0.0005%. or betweenabout 0.00025% and 0.000375%. In some embodiments, at least a portion ofthe struts are composed of struts having a length of 1 mm to 100 mm anda diameter ranging between 0.250 mm and 5 mm.

In an embodiment, an implant for interfacing with a bone structureincludes a web structure that is formed from a plurality of strutsjoined at nodes, wherein the web structure is configured to interfacewith human bone tissue. The web structure, in some embodiments, includesa first bone contact surface and a second bone contact surface. A firstportion of struts that comprise the space truss have a physical propertythat is different from a second portion of the struts that comprise thespace truss. The first portion of struts that comprise the space trussmay have: a deformation strength; a defined length; a diameter; adifferential diameter along its length; a density; a porosity; or anycombination of these physical properties; that is different from thesecond portion of the struts that comprise the space truss. In anembodiment, the space truss includes one or more central strutsextending from the first bone contact surface to the second bone contactsurface, wherein the central struts have a deformation strength that isgreater than or less than the surrounding struts. In an embodiment, thespace truss comprises one or more longitudinal struts extending parallelto the first bone contact surface and/or the second bone contactsurface, wherein the longitudinal struts have a deformation strengththat is greater than or less than the surrounding struts. The diameterof the first portion of the struts may be greater than a diameter of thesecond portion of the struts. The material used to form the firstportion of struts may be different from the material used to form thesecond portion of struts.

BRIEF DESCRIPTION OF THE DRAWINGS

Advantages of the present invention will become apparent to thoseskilled in the art with the benefit of the following detaileddescription of embodiments and upon reference to the accompanyingdrawings in which:

FIGS. 1A-1B illustrate views of an implant with lordosis, according toan embodiment.

FIGS. 2A-2D illustrate views of an implant without lordosis, accordingto an embodiment.

FIGS. 3A-3B illustrate a web structure formed with triangular-shapedbuilding blocks, according to an embodiment.

FIGS. 4A-4B illustrate a top structure of an internal web structure ofthe implant, according to an embodiment.

FIGS. 5A-5C illustrate progressive sectioned views of the implantshowing the internal structure of the implant, according to anembodiment.

FIG. 5D illustrates an isometric view of the implant, according to anembodiment.

FIGS. 6A-6D illustrate another configuration of the web structure,according to an embodiment.

FIG. 7 illustrates a random web structure, according to an embodiment.

FIG. 8 illustrates a flowchart of a method for making an implant,according to an embodiment.

FIG. 9 illustrates a flowchart of a method for implanting a spinalimplant, according to an embodiment.

FIG. 10 depicts a diagram of stresses distributed through an implant.

FIGS. 11A-C depict schematic diagrams of the effect of compression onosteoblast cells.

While the invention is susceptible to various modifications andalternative forms, specific embodiments thereof are shown by way ofexample in the drawings and will herein be described in detail. Itshould be understood, however, that the drawings and detaileddescription thereto are not intended to limit the invention to theparticular form disclosed, but on the contrary, the intention is tocover all modifications, equivalents, and alternatives falling withinthe spirit and scope of the present invention as defined by the appendedclaims. Note, the headings are for organizational purposes only and arenot meant to be used to limit or interpret the description or claims.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIGS. 1A-1B illustrate views of implant 100, according to an embodiment.The specifically depicted implant 100 may be used, for example, inanterior lumbar inter-body fusion (ALIT) or posterior lumbar inter-bodyfusion (PLIF), however, it should be understood that implant 100 nayhave a variety of shapes suitable for bone fusion applications. In someembodiments, implant 100 may include a web structure with one or moretrusses 102 (e.g., planar and space trusses). Implant 100 may be used invarious types of implants for humans or animals such as spinal implants,corpectomy devices, knee replacements, hip replacements, long bonereconstruction scaffolding, and cranio-maxifacial implants foot andankle, hand and wrist, shoulder and elbow (large joint, small joint,extremity as well as custom trauma implants). Other implant uses arealso contemplated.

As used herein a “truss structure” is a structure having one or moreelongate struts connected at joints referred to as nodes. Trusses mayinclude variants of a pratt truss, king post truss, queen post truss,town's lattice truss, planar truss, space truss, and/or a vierendeeltruss (other trusses may also be used). A “truss unit” is a structurehaving a perimeter defined by three or more elongate struts.”

As used herein a “planar truss” is a truss structure where all of thestruts and nodes lie substantially within a single two-dimensionalplane. A planar truss, for example, may include one or more “trussunits” where each of the struts is a substantially straight member suchthat the entirety of the struts and the nodes of the one or more trussunits lie in substantially the same plane. A truss unit where each ofthe struts is a substantially straight strut and the entirety of thestruts and the nodes of the truss unit lie in substantially the sameplane is referred to as a “planar truss unit.”

As used herein a “space truss” is a truss having struts and nodes thatare not substantially confined in a single two-dimensional plane. Aspace truss may include two or more planar trusses (e.g., planar trussunits) wherein at least one of the two or more planar trusses lies in aplane that is not substantially parallel to a plane of at least one ormore of the other two or more planar trusses. A space truss, forexample, may include two planar truss units adjacent to one another(e.g., sharing a common strut) wherein each of the planar truss unitslie in separate planes that are angled with respect to one another(e.g., not parallel to one another).

As used herein a “triangular truss” is a structure having one or moretriangular units that are formed by three straight struts connected atjoints referred to as nodes. For example, a triangular truss may includethree straight elongate strut members that are coupled to one another atthree nodes to from a triangular shaped truss. As used herein a “planartriangular truss” is a triangular truss structure where all of thestruts and nodes lie substantially within a single two-dimensionalplane. Each triangular unit may be referred to as a “triangular trussunit.” A triangular truss unit where each of the struts is asubstantially straight member such that the entirety of the struts andthe nodes of the triangular truss units lie in substantially the sameplane is referred to as a “planar triangular truss unit.” As used hereina “triangular space truss” is a space truss including one or moretriangular truss units.

In various embodiments, the trusses 102 of the web structure may includeone or more planar truss units (e.g., planar triangular truss units)constructed with straight or curved/arched members (e.g., struts)connected at various nodes. In some embodiments, the trusses 102 may bemicro-trusses. A “micro-truss” is a truss having dimensions sufficientlysmall enough such that a plurality of micro-trusses can be assembled orotherwise coupled to one another to form a web structure having a smallenough overall dimension (e.g., height, length and width) such thatsubstantially all of the web structure can be inserted into an implantlocation (e.g., between two vertebra). Such a web structure and itsmicro-trusses can thus be employed to receive and distribute throughoutthe web structure loading forces of the surrounding tissue (e.g.,vertebra, bone, or the like). In one embodiment, the diameters of thestruts forming the micro-truss may be between about 0.25 millimeters(mm) and 5 mm in diameter (e.g., a diameter of about 0.25 mm, 0.5 mm,0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, 1 mm, 2 mm, 3 mm, 4 mm, or 5 mm). In oneembodiment, a micro-truss may have an overall length or width of lessthan about 1 inch (e.g., a length less than about 0.9 in, 0.8 in, 0.7in, 0.6 in, 0.5 in, 0.4 in, 0.3 in, 0.2 in, 0.1 in).

As depicted, for example, in FIGS. 1A-1B, the web structure may extendthroughout implant 100 (including the central portion of implant 100) toprovide support throughout implant 100. Trusses 102 of implant 100 maythus support implant 100 against tensile, compressive, and shear forces.Web structure may also reinforce implant 100 along multiple planes. Theexternal truss structure may, for example, provide support againsttensile and compressive forces acting vertically through the implant,and the internal web structure may provide support against tensile,compressive, and shear forces along the various planes containing therespective trusses. In some embodiments, the web structure includestrusses 102 that form a triangulated web structure with multiple struts(e.g., struts 103 a-f) (struts are generally referred to herein as“struts 103”).

In one embodiment, web structure of the implant 100 may include aninternal web structure that is at least partially enclosed by anexternal truss structure. For example, in one embodiment, web structure101 may include an internal web structure that includes a space trusshaving at least a portion of the space truss surrounded by an externaltruss structure that includes one or more planar trusses formed with aplurality of planar truss units that lie substantially in a singleplane. FIG. 1A depicts an embodiment of implant 100 having an internalweb structure 104 and an external truss structure 105. In theillustrated embodiment, internal web structure 104 includes a spacetruss defined by a plurality of planar truss units 106 coupled at anangle with respect to one another such that each adjacent truss unit isnot co-planar with each adjacent truss units. Adjacent truss units mayinclude two truss units that share a strut and the respective two nodesat the ends of the shared strut.

In one embodiment, external truss structure 105 includes a plurality ofplanar trusses that are coupled about an exterior, interior or otherportion of the implant. For example, in the illustrated embodiment, theexternal truss structure 105 includes a series of planar trusses 107 a,bthat are coupled to one another. Planar truss 107 a is denoted by adashed line [- - - - -], planar truss 107 b is denoted by dotted-dashedline [- • -• -]. Each planar truss is formed from a plurality of planartruss units (e.g., triangular planar truss units. As depicted, planartruss 107 a includes four triangular planar truss units 108 a,b,c,dhaving a common vertex 110 and arranged to form a generally rectangularstructure that lies in a single common plane. In other words, the fourtriangular planar truss units are arranged to form a substantiallyrectangular structure having “X” shaped struts extend from one corner ofthe rectangular structure to the opposite corner of the rectangularstructure. As depicted, the substantially rectangular structure mayinclude a trapezoidal shape. As described in more detail below, thetrapezoidal shape may be conducive to providing an implant includinglordosis. Lordosis may include an angled orientation of surfaces (e.g.,top and bottom) of an implant that provides for differences in thicknessin anterior and posterior regions of the implant such that the implantis conducive for supporting the curvature of a vertebral column.

In one embodiment, the planar trusses that form the external truss arecoupled to one another, and are aligned along at least one axis. Forexample, in FIG. 1A, planar truss section 107 a is coupled to anadjacent planar truss 107 b. Planer truss sections 107 a,b are notparallel in all directions. Planar truss sections 107 a,b are, however,arranged parallel to one another in at least one direction (e.g., thevertical direction between the top and the bottom faces of implant 100).For example, planar trusses 107 a,b and the additional planar trussesare arranged in series with an angle relative to one another to form agenerally circular or polygon shaped enclosure having substantiallyvertical walls defined by the planar trusses and the planar truss unitsarranged in the vertical direction.

In one embodiment, the external truss portion may encompass the sides,top, and/or bottom of the implant. For example, in one embodiment, theexternal truss portion may include a top region, side regions, and/or abottom region. FIG. 1A depicts an embodiment of implant 100 whereinexternal truss portion 105 includes a top 111, bottom 112 and a sideregion 113. As described above, side region 113 includes a series ofplanar trusses arranged vertically to form a circular/polygon ring-likestructure that completely or at least partially surrounds the perimeterof the space truss disposed in the central portion of implant 100. Inthe depicted embodiment, top portion 111 of external truss structure 105includes a plurality of truss units coupled to one another to form aplanar truss that cover substantially all of the top region of internalweb structure 104. In the illustrated embodiment, the top portion 111spans entirely the region between top edges of the side portion 113 ofexternal truss structure 105. In the illustrated embodiment, top portion111 is formed from a single planar truss that includes a plurality oftruss units that lie in substantially the same plane. In other words,the planar truss of top portion 111 defines a generally flat surface.Although difficult to view in FIG. 1, the underside of implant 100 mayinclude the bottom portion 112 having a configuration similar to that ofthe top portion 111. In other embodiments, external truss structure 105may include a partial side, top and/or bottom external truss portions.Or may not include one or more of the side, top and bottom externaltruss portions. For example, as described in more detail below, FIG. 2Cdepicts an embodiment of implant 100 that includes an internal webstructure formed from space trusses, that does not have an externaltruss structure.

In some embodiments, implant 100 may be formed from a biocompatiblematerial such as a titanium alloy (e.g., γTitanium Aluminides), cobalt,chromium, stainless steel, Polyetheretherketone (PEEK), ceramics, etc.Other materials are also contemplated. In some embodiments, implant 100may be made through a rapid prototyping process (e.g., electron beammelting (EBM) process) as further described below. Other processes arealso possible (e.g., injection molding, casting, sintering, selectivelaser sintering (SLS), Direct Metal Laser Sintering (DMLS), etc). SLSmay include laser-sintering of high-performance polymers such as thatprovided by EOS of North America, Inc., headquartered in Novi, Mich.,U.S.A. High-performance polymers may include various forms of PEEK(e.g., HP3 having a tensile strength of up to about 95 mega Pascal (MPa)and a Young's modulus of up to about 4400 MPa and continuous operatingtemperature between about 180° C. (356° F.) and 260° C. (500° F.)).Other materials may include PA 12 and PA 11 provided by EOS of NorthAmerica, Inc.

As described above, in some embodiments the web structure may be formedfrom a plurality of triangular planar truss units. In some embodiments,the planar truss units may be coupled to each other to definepolyhedrons that define the internal web structure. Examples ofpolyhedron structures that may be created by joining planar truss unitsinclude, but are not limited to, tetrahedrons, pentahedrons,hexahedrons, heptahedrons, pyramids, octahedrons, dodecahedrons,icosahedrons, and spherical fullerenes. In some embodiments, such asthose described above, the space truss of the web structure may connectmultiple midpoints of tetrahedron building blocks and include a regularpattern of tetrahedron blocks arranged adjacent one another. In someembodiments, the web structure may not include a pattern of geometricalbuilding blocks. For example, FIG. 7 illustrates an irregular pattern ofstruts that may be used in an implant 905. Other web structures are alsocontemplated. Examples of implants composed of a web structure aredescribed in U.S. Published Patent Applications Nos.: 2010/0161061;2011/0196495; 20110313532; and 2013/0030529, each of which isincorporated herein by reference.

FIGS. 3A-3B illustrate a schematic view of a portion of an internal webstructure formed with space units formed from triangular planar trussunits. Triangular planar truss units may be joined together to formtetrahedrons 300 a,b that may also be used as building blocks (otherpatterns from the triangles are also contemplated). Other buildingblocks are also contemplated (e.g., square-shaped building blocks). Insome embodiments, a web structure may include a single tetrahedron, suchas tetrahedron 300 a or 300 b alone or in combination with one or moreother polyhedron. In some embodiments, a web structure may include twoor more tetrahedrons 300 a,b. Tetrahedron 300 a may include fourtriangular faces in which three of the four triangles meet at eachvertex. In some embodiments, two tetrahedrons 300 a and 300 b may beplaced together at two adjacent faces to form space truss 313 with ahexahedron-shaped frame (including six faces). Hexahedron-shaped spacetruss 313 may include first vertex 301, second vertex 309, third vertex303, fourth vertex 305, and fifth vertex 307. Common plane 311 may beshared by two tetrahedrons (e.g., common plane 311 may include thirdvertex 303, fourth vertex 305, and fifth vertex 307) to form ahexahedron with first vertex 301 and second vertex 309 spaced away fromcommon plane 311. As depicted, the center portion of the triangularshaped building blocks may have a void region in their center that doesnot include any additional members (e.g., no members other than thestruts forming the triangular shaped building blocks) extending therethrough.

As seen in FIG. 3B, in some embodiments, multiple hexahedron-shapedspace trusses 313 may be arranged in a side-by-side manner. Two spacetrusses 313 of implant 100 may be connected via their first vertices 301a,b through strut 103 r and connected via their second vertices 309 a,bthrough strut 103 t. Similarly, two space trusses 313 may be connectedvia their first vertices 301 c,d through strut 103 p and connected viatheir second vertices 309 c,d through strut 103 s. Other connections arealso possible. For example, space trusses 313 may connect directlythrough side vertices (e.g., directly through corresponding vertices(such as vertices 303 a,b) and/or share a common strut (such as strut103 u)) and/or through a side face (e.g., side faces 111 a,b).

FIG. 4A illustrates additional struts 103 (e.g., struts 103 p and 103 r)connecting the first vertices (represented respectively by 301 a, 301 b,301 c, and 301 d) of four hexahedron-shaped space trusses in implant100. FIG. 4B illustrates additional struts 103 (e.g., struts 103 s and103 t) connecting second vertices 309 (represented respectively by 309a, 309 b, 309 c, and 309 d) of four hexahedron-shaped space trusses inimplant 100. In some embodiments, additional struts 103 may also be usedinternally between one or more vertices of the web structures to formadditional trusses (e.g., see web structures in FIGS. 1A-2B) (otherstructures are also possible).

As shown in FIG. 1A, top surface 115 a and bottom surface 115 b ofimplant 100 may include triangles, squares, circles or other shapes(e.g., a random or custom design). Top and bottom surfaces 115 a,b maybe used to connect the top and bottom vertices of various geometricalbuilding blocks used in the web structure of implant 100. For example,each vertex may be connected through struts to the neighboring verticesof other geometrical building blocks. Top surface 115 a may includeother strut networks and/or connections. In some embodiments, bottomsurface 115 b may mirror the top surface (and/or have other designs). Insome embodiments, top surface 115 a and bottom surface 115 b may engagerespective surfaces of two adjacent vertebrae when implant 100 isimplanted.

As depicted in FIG. 1B, implant 100 may include lordosis (e.g., an anglein top and/or bottom surfaces 115 a,b approximately in a range of 4 to15 degrees (such as 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, or 15degrees)) to further support the adjacent vertebrae when implanted. Asdescribed above, lordosis may include an angled orientation of surfaces(e.g., top and bottom) that provide for differences in thickness in theanterior and posterior portions of the implant such that the implant isconducive for supporting the curvature of a vertebral column. In theillustrated embodiment, the thickness of implant 100 is greater at ornear the anterior portion 118 and lesser at or near the posteriorportion 120 of the implant. In the illustrated embodiment, the sideportions of external truss structure are arranged substantiallyvertically, and the lordosis is formed by the angles of the top portion111 and bottom portion 112 of external truss structure. For example, inthe illustrated embodiment, top portion 111 and bottom portion 112 ofexternal truss structure are not perpendicular to the vertical planedefined by the side portion 113. Rather, the top portion 111 and bottomportion 112 are arranged with an acute angle relative to the verticalplane of side portion 113 at or near the anterior region 118 of implant100 and with an obtuse angle relative to the vertical plane of sideportion 113 at or near posterior region 120 of implant 100. As depicted,the vertical struts that form the planar truss of side portion 113 ofexternal truss structure proximate posterior region 120 of implant 100are shorter than struts that form side portion of external trussstructure proximate anterior region 118 of implant 100. In theillustrated embodiment, in which the vertical trusses are substantiallyevenly spaced, the struts forming the “X” cross members of the sideplanar trusses proximate the posterior region 120 of implant 100 areshorter than struts forming the “X” cross members of the side planartrusses proximate the anterior region 118 of implant 100. Otherembodiments may include variations in the arrangement of the trusses toprovide various configurations of the implant. For example, in someembodiments only one or neither of the top and bottom external trussportions may be non-perpendicular to the side portions of the externaltruss proximate the anterior and posterior portions of the implant.Further, the side, top, and/or bottom portions may include multipleplanar trusses angled relative to one another in any orientation. Forexample, the top or bottom portions may include four planar trusses,each formed of multiple truss units, such that the portion(s) includes apyramidal like shape.

In some embodiments, the implant may not include lordosis. For example,FIGS. 2A-2B illustrate two views of an embodiment of an implant 200without lordosis. In some embodiments, the top surface and bottomsurface may not include connecting struts. For example, FIGS. 2C-2Dillustrate two views of implant 250 without outer struts (e.g., withoutexternal truss portions formed of planar trusses). In the illustratedembodiment, implant 250 includes an internal web structure and does notinclude an external truss structure. For example, in the illustratedembodiment, the exterior faces of implant 250 are defined by a pluralityof truss units that are angled relative to each of its adjacent trussunits. The relative alignment of the truss units results in a non-planarexterior that includes a plurality of pointed junctions. The pointedjunctions (e.g., pointed junction 201) may operate to dig into thesurrounding bone to hold the implant in place (for example, if theimplant is being used in a corpectomy device).

FIGS. 5A-5C illustrate progressive sectioned views of implant 100showing the internal structure of implant 100, according to anembodiment. FIG. 5A illustrates a sectioned view of a lower portion ofimplant 100. Bottom surface 115 b is shown with various struts (e.g.,struts 103) extending upward from bottom surface 115 b. FIG. 5Billustrates a sectioned view approximately mid-way through implant 100.Struts, such as struts 103 e,f, shared by various stacked tetrahedronsin the web structure are shown. Some struts extend through centralportion 501 a and/or 501 b of implant 100. FIG. 5B also shows centralportions 501 a,b of implant 100. In some embodiments, central portion501 a may include a rectangular region that has a width of approximately50% of the implant width, a height of approximately 50% of the implantheight, and a length of approximately 50% of the implant length andlocated in the center of implant 100. In some embodiments, centralportion 501 b may encompass a region (e.g., a spherical region, squareregion, etc.) of approximately a radius of approximately ⅛ to ¼ of thewidth of implant 100 around a position located approximately at one halfthe width, approximately one half the length, and approximately one-halfthe height of implant 100 (i.e., the center of implant 100). Othercentral portions are also contemplated. For example, the central portionmay include a square region with a length of one of the sides of thesquare region approximately ¼ to ½ the width of implant 100 around aposition approximately at one half the width, approximately one half thelength, and approximately one half the height of the implant. An exampleheight 502 a, width 502 b, and length 502 c, is shown in FIG. 5D. Insome embodiments, the height may be up to about 75 mm or more. In someembodiments, such as those used for long bone reconstruction, the widthand/or length could be approximately 7 inches or longer. In someembodiments, the width, length, and/or height may vary along implant 100(e.g., the height may vary if the implant includes lordosis). The heightmay be taken at one of the opposing sides, the middle, and/or may be anaverage of one or more heights along the length of implant 100. The webstructure may extend through central portion 501 a,b of the implant(e.g., at least one strut of the web structure may pass at leastpartially through central portion 501 a,b). FIG. 5C illustrates anothersectioned view showing sectioned views of top tetrahedrons in the webstructure. FIG. 5D shows a complete view of implant 100 including topsurface 115 a with vertices 301 a-d.

FIGS. 6A-6D illustrate alternate embodiments of an implant. In someembodiments, different sections of the hexahedron-shaped geometricdesign may be used. For example, as seen in FIG. 6A, the bottom half ofthe hexahedron-shaped geometric design may be used (primarily includingthe lower tetrahedron structures). If using the bottom half of thedesign, implant 600 may be expanded proportionately to have similaroverall dimensions as the hexahedron-shaped geometric design (e.g., thetetrahedrons may be expanded to approximately twice the height of thetetrahedrons in the hexahedron-shaped geometric design to give implant600 a height approximately the same as the hexahedron-shaped geometricdesign). In some embodiments, implant 600 may also be angled (e.g., ontop surface 601 a and/or bottom surface 601 b) to provide implant 600with lordosis to, in some embodiments, have a better fit between thevertebral endplates. Top surface 601 a and/or bottom surface 601 b mayalso include struts to connect nodes of implant 600 (e.g., see the strutnetwork on the top surface in FIG. 6a ). Other patterns of struts fortop surface 601 a and/or bottom surface 601 b may also be used. In someembodiments, implant 600 may not include negative angles between strutsand may thus be easier to create through a casting or molding process.

FIGS. 6C-6D illustrate another alternate embodiment of an implant. Insome embodiments, approximately the middle 40 to 60 percent of thehexahedron-shaped geometric design may be used in implant 650. Forexample, if an overall height of the hexahedron-shaped geometric designis approximately 37 mm, approximately the bottom 10 mm and approximatelythe top 10 mm of the design may be removed and approximately the middle17 mm of the design may be used for the implant. Middle portion ofimplant 650 may then be expanded proportionately such that theapproximate height of the expanded design may be approximately 37 mm (ora different height as needed). Top surface 651 a and bottom surface 651b may include a network of struts (e.g., see the struts on top surface651 a of FIG. 6C) (other networks of struts are also contemplated).Other portions of the design for the implant are also contemplated(e.g., the top half of the design shown in FIG. 1A, the bottom half ofthe design shown in FIG. 1A, etc). Design portions may beproportionately expanded to meet specified dimensions (e.g., specifiedheight, width, and length). In some embodiments, the amount of strutsmay be reduced or material in the implant may be redistributed so thatsome struts may have a larger diameter and some may have a smallerdiameter (e.g., the different diameters may reinforce against differentdirectional forces). In some embodiments, a partial-design cage may beused (e.g., with half of the web structure so that the structureincludes a tetrahedron. Further, in some embodiments, the implant mayinclude angled surfaces (e.g., an angled top surface 651 a and/or angledbottom surface 651 b) to provide lordosis for implants to be implantedbetween the vertebral endplates.

In some embodiments, the web structure of an implant may distributeforces throughout the implant when implanted. For example, theconnecting struts of the web structure may extend throughout the core ofan implant, and the interconnectivity of struts may disperse the stressof compressive forces throughout implant to reduce the potential ofstress risers (the distribution of forces throughout the implant mayprevent concentration of stress on one or more portions of the vertebraethat may otherwise result in damage to the vertebrae).

In some embodiments, the web structure of an implant (e.g., the externaland internal struts of the implant) may also provide surface area forbone graft fusion. For example, the web structure extending throughoutan implant may add additional surface areas (e.g., on the surface of thestruts making up the implant) to fuse to the bone graft material andprevent bone graft material from loosening or migrating from theimplant. In some embodiments, the web structure may also support bonein-growth. For example, when implanted, adjacent bone (e.g., adjacentvertebrae if the implant is used as a spinal implant) may grow over atleast a portion of struts of the implant. The bone growth and engagementbetween the bone growth and the implant may further stabilize theimplant. In some embodiments, the surfaces of the implant may be formedwith a rough surface to assist in bone in-growth adhesion.

In some embodiments, struts may have a diameter approximately in a rangeof about 0.025 to 5 millimeters (mm) (e.g., 1.0 mm, 1.5 mm, 3 mm, etc).Other diameters are also contemplated (e.g., greater than 5 mm). In someembodiments, the struts may have a length approximately in a range of0.5 to 20 mm (e.g., depending on the implant size needed to, forexample, fit a gap between vertebral endplates). As another example,struts may have a length approximately in a range of 30-40 mm for a hipimplant. In some embodiments, the reduced strut size of the webstructure may allow the open cells in implant 100 to facilitate bonegrowth (e.g., bone may grow through the open cells once implant 100 isimplanted in the body). Average subsidence for implants may beapproximately 1.5 mm within the first 3 weeks post op (other subsidenceis also possible (e.g., approximately between 0.5 to 2.5 mm)). A strutsize that approximately matches the subsidence (e.g., a strut size ofapproximately 1.5 mm in diameter and a subsidence of approximately 1.5mm) may result in a net 0 impedance (e.g., the bone growth growingaround the struts) after the implant has settled in the implantedposition. The net 0 impedance throughout the entire surface area of theimplant/vertebrae endplate interface may result in a larger fusioncolumn of bone that may result in more stable fusion. Other fusioncolumn sizes are also contemplated. The configuration of the implant mayredistribute the metal throughout the implant. In some embodiments, arim may not be included on the implant (in some embodiments, a rim maybe included). The resulting bone growth (e.g., spinal column) may growthrough the implant.

In some embodiments, greater than 50% of the interior volume of implant100 may be open. In some embodiments, greater than 60%, greater than70%, and/or greater than 80% of implant 100 may be open (e.g., 95%). Insome embodiments, the open volume may be filled with bone growthmaterial. For example, cancellous bone may be packed into anopen/internal region of implant.

In some embodiments, at least a portion of the surfaces of the implantmay be coated/treated with a material intend to promote bone growthand/or bone adhesion and/or an anitmicrobial agent to preventinfections. For example, in some embodiments, the surface of the strutsmay be coated with a biologic and/or a bone growth factor. In someembodiments, a biologic may include a coating, such as hydroxyapatite,bone morphogenetic protein (BMP), insulinlike growth factors I and II,transforming growth factor-beta, acidic and basic fibroblast growthfactor, platelet-derived growth factor, and/or similar bone growthstimulant that facilitates good biological fixation between the bonegrowth and a surface of the implant. In some embodiments, a bone growthfactor may include a naturally occurring substance capable ofstimulating cellular growth, proliferation and cellular differentiation(e.g., a protein or steroid hormone). In some embodiments, the surfaceof the implant (e.g., the struts, the external truss structure, etc.)may be coated with collagen.

In some embodiments, a biologic and/or growth factor may be secured to acentral region of an implant. For example, in some embodiments, abiologic or growth factor may be provided on at least a portion of astrut that extends through central portion 501 a and/or 501 b of implant100, see FIG. 5B. Such an embodiment may enable the delivery of abiologic and or a growth factor to a central portion of an implant. Forexample, the biologic or growth factor may be physically secured to astrut in a central portion of the implant as opposed to being packedinto an open volume that does not include a strut provided therein forthe physical attachment of the biologic and/or growth factor.

As the implant settles into the implant site, subsidence may placeadditional pressure on the bone graft material (which may already beunder compressive forces in the implant) and act to push the bone graftmaterial toward the sides of the implant (according to Boussinesq'stheory of adjacent material, when a force is applied to a member that isadjacent to other materials (such as sand, dirt, or bone graft material)the force against the member creates a zone of increased pressure (e.g.,60 degrees) in the adjacent material). Struts of the implant may resistbone graft material protrusion from the sides of the web structure andmay increase the pressure of the bone graft material. Bone graftmaterial may need to be implanted in a higher-pressure environment tocreate an environment conducive to strong bone growth (e.g., accordingto Wolf's law that bone in a healthy person or animal will adapt to theloads it is placed under). The web structure may thus increase thechance of stronger fusion.

Web structures formed from other truss configurations are alsocontemplated. For example, the trusses may include a series of packingtriangles, a two-web truss, a three-web truss, etc. Further, the webstructure for an implant may include one or more trusses as described inU.S. Pat. No. 6,931,812 titled “Web Structure and Method For Making theSame”, which issued Aug. 23, 2005, which is hereby incorporated byreference in its entirety as though fully and completely set forthherein.

FIG. 8 illustrates a flowchart of a method for making an implant. Insome embodiments, an implant may be made through rapid prototyping(e.g., electron beam melting, laser sintering, etc). It should be notedthat in various embodiments of the methods described below, one or moreof the elements described may be performed concurrently, in a differentorder than shown, or may be omitted entirely. Other additional elementsmay also be performed as desired. In some embodiments, a portion or theentire method may be performed automatically by a computer system.

At 1001, a three dimensional model of an implant is generated and storedin a storage medium accessible to a controller operable to control theimplant production process. At 1003, a layer of material (e.g., apowder, liquid, etc.) is applied to a support. In some embodiments, thepowder may include γTiAl (γTitanium Aluminides) which may be a highstrength/low weight material. Other materials may also be used. Thepowder may be formed using a gas atomization process and may includegranules with diameters approximately in a range of 20 to 200micrometers (μm) (e.g., approximately 80 μm). The powder may bedelivered to the support through a distributer (e.g., delivered from astorage container). The distributer and/or the support may move duringdistribution to apply a layer (e.g., of powder) to the support. In someembodiments, the layer may be approximately a uniform thickness (e.g.,with an average thickness of 20 to 200 micrometers (μm)). In someembodiments, the distributer and support may not move (e.g., thematerial may be sprayed onto the support). At 1005, the controller movesan electron beam relative to the material layer. In some embodiments,the electron beam generator may be moved, and in some embodiments thesupport may be moved. If the material is γTiAl, a melting temperatureapproximately in a range of 1200 to 1800 degrees Celsius (e.g., 1500degrees Celsius) may be obtained between the electron beam and thematerial. At 1007, between each electron beam pass, additional materialmay be applied by the distributer. At 1009, the unmelted material isremoved and the implantcooled (e.g., using a cool inert gas). In someembodiments, the edges of the implant may be smoothed to remove roughedges (e.g., using a diamond sander). In some embodiments, the implantmay include rough edges to increase friction between the implant and thesurrounding bone to increase adhesion of the implant to the bone.

Other methods of making an implant are also contemplated. For example,an implant may be cast or injection molded. In some embodiments,multiple parts may be cast or injection molded and joined together(e.g., through welding, melting, etc). In some embodiments, individualstruts forming the implant may be generated separately (e.g., bycasting, injection molding, etc.) and welded together to form theimplant. In some embodiments, multiple implants of different sizes maybe constructed and delivered in a kit. A medical health professional maychoose an implant (e.g., according to a needed size) during the surgery.In some embodiments, multiple implants may be used at the implant site.

Specialized tools may be used to insert the implants described herein.Examples of tools that may be used are described in U.S. PublishedPatent Applications Nos.: 2010/0161061; 2011/0196495; 20110313532; and2013/0030529, each of which is incorporated herein by reference.

FIG. 9 illustrates a flowchart of a method for implanting a spinalimplant, according to an embodiment. It should be noted that in variousembodiments of the methods described below, one or more of the elementsdescribed may be performed concurrently, in a different order thanshown, or may be omitted entirely. Other additional elements may also beperformed as desired. In some embodiments, a portion or the entiremethod may be performed automatically by a computer system.

At step 1301, an intersomatic space is accessed. For example, ananterior opening may be made in a patient's body for an anterior lumbarinter-body fusion (ALIF) approach or a posterior opening may be made fora posterior lumbar inter-body fusion (PLIF) approach. At 1303, at leasta portion of the intersomatic space is excised to form a cavity in theintersomatic space. At 1305, the implant is inserted into the cavity inthe intersomatic space. In some embodiments, a handler, or some otherdevice, is used to grip the implant. In some embodiments, a force may beapplied to the implant (e.g., through a hammer) to insert the implantinto the cavity. At 1307, before and/or after insertion of the implant,the implant and/or space in the cavity may be packed with bone graftmaterial. At 1309, the access point to the intersomatic space may beclosed (e.g., using sutures).

In some embodiments, the implant may be customized. For example, threedimensional measurements and/or shape of the implant may be used toconstruct an implant that distributes the web structure throughout athree-dimensional shape design.

In some embodiments, a truss/web structure may be disposed on at least aportion of an implant to facilitate coupling of the implant to anadjacent structure. For example, where an implant is implanted adjacenta bony structure, one or more truss structures may be disposed on and/orextend from a surface (e.g., an interface plate) of the implant that isintended to contact, and at least partially adhere to, the bonystructure during use. In some embodiments, such as those including anintervertebral implant disposed between the end plates of two adjacentvertebrae during, one or more truss structures may be disposed on acontact surface of the intervertebral implant to facilitate bone growththat enhances coupling of the intervertebral implant to the bonystructure. For example, a truss structure may include one or more strutsthat extend from the contact surface to define an open space for bonegrowth therethrough, thereby enabling bone through growth to interlockthe bone structure and the truss structure with one another to couplethe implant to the bony structure at or near the contact face. Suchinterlocking bone through growth may inhibit movement between theimplant and the bony structure which could otherwise lead to loosening,migration, subsidence, or dislodging of the implant from the intendedposition. Similar techniques may be employed with various types ofimplants, including those intended to interface with tissue and/or bonestructures. For example, a truss structure may be employed on a contactsurface of knee implants, in a corpectomy device, in a hip replacement,in a knee replacement, in a long bone reconstruction scaffold, or in acranio-maxifacial implant hip implants, jaw implant, an implant for longbone reconstruction, foot and ankle implants, shoulder implants or otherjoint replacement implants or the like to enhance adherence of theimplant to the adjacent bony structure or tissue. Examples of trussstructures, and other structures, that may extend from the surface of animplant to facilitate coupling of the implant to an adjacent structureare described in U.S. Published Patent Application No. 2011/0313532,which is incorporated herein by reference.

While implants described herein are depicted as being composed ofsubstantially straight struts, it should be understood that the strutscan be non-linear, including, but not limited to curved, arcuate andarch shaped. Examples of implants having non-linear struts are describedin U.S. patent application Ser. No. 13/668,968, which is incorporatedherein by reference.

It is known that osteoblasts under an appropriate load produce bonemorphogenetic protein (“BMP”). BMPs are a group of growth factors alsoknown as cytokines and as metabologens. BMPs act as morphogeneticsignals that signal the formation of bone (i.e., an osteogeneticresponse). Thus, by increasing the production of one or more BMPs theosteogentic response to an implant is increased, creating an implantthat is integrated into the newly formed bone.

A web structure that includes a plurality of joined truss units exhibitsa number of deformations in response to loading. FIG. 10 below depictssome of the forces that are dispersed along the struts of the trussunits that make up the web structure. When used as a bone implant, webstructures as described herein may promote the growth of bone in andaround the web structure, in part, because of the enhanced BMPproduction. As shown in FIGS. 11A-C, osteoblasts become attached to thestruts of a web structure. Under loading, the micro strain in the strutscauses localized deformation which in turn transfers the strain to theadhered osteoblasts which cause the osteoblasts to elute BMP.

FIG. 11A depicts a schematic diagram of an implant 400 that includes aspace truss 410. Bone structures, not shown, are typically disposedagainst a top face 420 and a bottom face 425 of implant 400. During use,the stress from the contacting bone structures (denoted by arrows 430)can cause implant 400 to lengthen (denoted by arrow 435) as the implantis compressed. This lengthening can have a beneficial effect on theformation of BMP by osteoblasts that adhere to the implant. Adjacentbone adds compression forces to the slanted struts. This compression maylead to bone remodeling. The combination of the two forces (compressionand lengthening) creates bone growth/remodeling which leads toaccelerated healing and achieving a mature fusion in a shorter amount oftime as compared to predicate devices.

FIG. 11B depicts a close-up view of strut 415 of implant 400. Strut 415,in FIG. 11B is shown in a non-elongated state. This may represent thestate of strut 415 when the implant is not under load from thecontacting bone structures. Osteoblasts are depicted as adhered to strut415. The osteoblasts are shown in their normal, non-elongated form. FIG.11C depicts strut 415 in an elongated state, which exists when the bonestructures are applying a compressive force to implant 400. As shown,the osteoblasts are believed to be stretched due to the elongation ofstrut 415. Elongation of the osteoblasts lead to an influx of calciumwhich is then converted into BMP and eluted back out. Studies have shownthat the creating a microstrain in the osteoblasts of between 500με and2000με or between about 1000με and about 1500με enhances the productionof BMP. Alternatively, the production of BMP may be attained when thelength of the attached osteoblasts is changed between about 0.05% andabout 0.2% or between about 0.1% and about 0.15%. Configuring a trusssystem to intentionally create lengthening/microstrain in osteoblastsmay reduce the time needed for the bone structure to be repaired.

In an embodiment, an implant for interfacing with a bone structureincludes a web structure comprising a plurality of struts joined atnodes. The web structure is configured to interface with human bonetissue. In one embodiment, a diameter and/or length of the struts arepredetermined such that when the web structure is in contact with thebone structure, BMP production from osteoblasts adhering to the implantsurface is achieved. In one embodiment, the diameter and/or length ofthe struts is predetermined so that at least a portion of the strutscreate a microstrain in the adhered osteoblasts of between about 1 and5000 microstrain, 500με and about 2000με or between about 1000με andabout 1500με. In an embodiment, the diameter and/or length of the strutsis predetermined so that at least a portion of the struts create achange in length of the adhered osteoblasts of between about 0.05% andabout 0.2% or between about 0.1% and about 0.15%.

An implant may be prepared having struts of a length of between about 1to 100 mm. The diameter of the struts may be set such that the strutundergoes a change of length of between about 0.05% and 0.2% when theweb structure is in contact with the bone structure. In someembodiments, the diameter of the struts is predetermined such that thestrut undergoes a change of length of between about 0.000125% and0.0005% or between about 0.00025% and 0.000375%.

Any implant described herein may be modified so that at least a portionof the struts the form the web structure produce the appropriatemicrostrain/lengthening of adhered osteoblasts. In some embodiments,most if not all of the struts that form the web structure of an implantmay be ‘programmed’ (or designed) to stimulate BMP production. In otherembodiments, some struts may be programmed/designed for BMP production,while other struts have different physical properties than theprogrammed struts.

An implant may be optimized to distribute stresses encountered by theimplant. Most implants used for bone repair are placed in locations thatapply non-uniform stress to the implant. The non-uniform stress createsdifferent forces across the implant. If an implant is designed towithstand a certain homogenous force, the implant may fail whensubjected to non-uniform stress. In a non-uniform stress situation, someof the stress on the implant may be sufficient to deform the implant. Itis desirable to have an implant that is customized to the expectednon-uniform stress that will be encountered in the bone structure beingrepaired.

In an embodiment, an implant for interfacing with a bone structure,includes a web structure having a plurality of struts joined at nodes.The web structure is configured to interface with human bone tissue, andhas a first bone contact surface and a second bone contact surface. Afirst portion of struts that are part of the space truss have a physicalproperty that is different from a second portion of the struts that area part of the space truss. In this manner an implant may be createdwhich optimizes the stresses encountered by the implant to help inhibitfailure of the implant.

In one embodiment, the first portion of struts that are part of thespace truss have a deformation strength that is different from a secondportion of the struts that are a part of the space truss. The spacetruss may include one or more central struts extending from the firstbone contact surface to the second bone contact surface. The centralstruts may have a deformation strength that is greater than or less thanthe surrounding struts, depending on the location of the implant. Thespace truss may include one or more longitudinal struts extendingparallel to the first bone contact surface and/or the second bonecontact surface, wherein the longitudinal struts have a deformationstrength that is greater than or less than the surrounding struts.

The physical properties of the struts of the implant may be varied suchthat the diameter of the first portion of the struts is greater than adiameter of the second portion of the struts. In some embodiments, thefirst portion of struts are formed from a material that is differentfrom the material used to form the second portion of struts. In someembodiments, the first portion of struts have a diameter that isdifferent from the diameter of the second portion of struts. In someembodiments, the first portion of struts have a density that isdifferent from the density of the second portion of struts. In someembodiments, he first portion of struts have a porosity that isdifferent from the porosity of the second portion of struts. Anycombination of these different physical properties may be present in animplant to help optimize the distribution of stress throughout theimplant.

In this patent, certain U.S. patents, U.S. patent applications, andother materials (e.g., articles) have been incorporated by reference.The text of such U.S. patents, U.S. patent applications, and othermaterials is, however, only incorporated by reference to the extent thatno conflict exists between such text and the other statements anddrawings set forth herein. In the event of such conflict, then any suchconflicting text in such incorporated by reference U.S. patents, U.S.patent applications, and other materials is specifically notincorporated by reference in this patent.

In accordance with the above descriptions, in various embodiments, animplant may include a web structure. The web structure for the implantmay include a micro truss design. In some embodiments, the micro trussdesign may include a web structure with multiple struts. Other webstructures are also contemplated. The web structure may extendthroughout the implant (including a central portion of the implant). Theweb structure may thus reinforce the implant along multiple planes(including internal implant load bearing) and provide increased area forbone graft fusion. The web structure may be used in implants such asspinal implants, corpectomy devices, hip replacements, kneereplacements, long bone reconstruction scaffolding, andcranio-maxillofacial implants foot and ankle, hand and wrist, shoulderand elbow (large joint, small joint, extremities). Other implant usesare also contemplated. In some embodiments, the web structure for theimplant may include one or more geometric objects (e.g., polyhedrons).In some embodiments, the web structure may not include a pattern ofgeometrical building blocks (e.g., an irregular pattern of struts may beused in the implant). In some embodiments, the web structure may includea triangulated web structure including two or more tetrahedrons. Atetrahedron may include four triangular faces in which three of the fourtriangles meet at each vertex. The web structure may further include twotetrahedrons placed together at two adjacent faces to form a webstructure with a hexahedron-shaped frame (including six faces). In someembodiments, multiple hexahedron-shaped web structures may be arrangedin a side-by-side manner. The web structures may connect directlythrough side vertices (e.g., two or more hexahedron-shaped webstructures may share a vertex). In some embodiments, the web structuremay be angled to provide lordosis to the implant.

Further modifications and alternative embodiments of various aspects ofthe invention may be apparent to those skilled in the art in view ofthis description. For example, although in certain embodiments, strutshave been described and depicts as substantially straight elongatedmembers, struts may also include elongated members curved/arched alongat least a portion of their length. Accordingly, this description is tobe construed as illustrative only and is for the purpose of teachingthose skilled in the art the general manner of carrying out theinvention. It is to be understood that the forms of the invention shownand described herein are to be taken as embodiments. Elements andmaterials may be substituted for those illustrated and described herein,parts and processes may be reversed, and certain features of theinvention may be utilized independently, all as would be apparent to oneskilled in the art after having the benefit of this description of theinvention. Changes may be made in the elements described herein withoutdeparting from the spirit and scope of the invention as described in thefollowing claims. Furthermore, it is noted that the word “may” is usedthroughout this application in a permissive sense (i.e., having thepotential to, being able to), not a mandatory sense (i.e., must). Theterm “include”, and derivations thereof, mean “including, but notlimited to”. As used in this specification and the claims, the singularforms “a”, “an” and “the” include plural referents unless the contentclearly indicates otherwise. Thus, for example, reference to “a strut”includes a combination of two or more struts. The term “coupled” means“directly or indirectly connected”.

What is claimed is:
 1. An implant for interfacing with a bone structure,comprising: a web structure comprising a plurality of struts joined atnodes to form a space truss comprising a plurality of planar trussunits, wherein the web structure is configured to interface with bonetissue, and wherein the plurality of planar truss units are coupled toone another such that one or more planar truss units lie in a plane thatis not substantially parallel to a plane of a planar truss unit thatshares at least one strut with the one or more planar truss units;wherein a diameter and/or length of the struts and/or density of the webstructure are predetermined such that when the web structure is incontact with the bone at least a portion of the struts create amicrostrain in adhered osteoblasts, bone matrix, or lamellar tissue; andwherein one or more angles defined by two struts and a node of one ormore of the planar truss units are different than one or morecorresponding angles defined by two struts and a node of one or moreother planar truss units, wherein connecting exterior surface strutscouple the nodes of the non-equivalent angle planar truss units to eachother such that the implant has a varied height.
 2. The implant of claim1, where in the diameter and/or length of the struts and/or density ofthe web structure is predetermined so that the struts, under load,create a microstrain, in adhered osteoblasts, bone matrix, or lamellartissue, wherein the microstrain is within a range that stimulates anosteogenetic response.
 3. The implant of claim 1, wherein the diameterand/or length of the struts and/or density of the web structure ispredetermined so that at least a portion of the struts create amicrostrain in the adhered osteoblasts, bone matrix, or lamellar tissueof between about 1με and about 5000με.
 4. The implant of claim 1,wherein the diameter and/or length of the struts and/or density of theweb structure is predetermined so that at least a portion of the strutscreate a microstrain in the adhered osteoblasts, bone matrix, orlamellar tissue of between about 500με and about 2000με.
 5. The implantof claim 1, wherein the diameter and/or length and/or density of the webstructure of the struts is predetermined so that at least a portion ofthe struts create a microstrain in the adhered osteoblasts, bone matrix,or lamellar tissue of between about 1000με and about 1500με.
 6. Theimplant of claim 1, wherein the diameter and/or length and/or density ofthe web structure of the struts is predetermined so that at least aportion of the struts create a change in length of the adheredosteoblasts of between about 0.05% and about 0.2%.
 7. The implant ofclaim 1, wherein the diameter and/or length and/or density of the webstructure of the struts is predetermined so that at least a portion ofthe struts create a change in length of the adhered osteoblasts ofbetween about 0.1% and about 0.15%.
 8. The implant of claim 1, whereinthe struts have a length of between about 1 mm to about 100 mm, andwherein a diameter of the strut is predetermined such that the strutscreate a change in length of the adhered osteoblasts of between about0.05% and 0.2% when the web structure is in contact with the bonestructure.
 9. The implant of claim 1, wherein the diameter of the strutis predetermined such that the strut undergoes a change of length ofbetween about 0.000125% and 0.0005%.
 10. The implant of claim 1, whereinthe diameter of the strut is predetermined such that the strut undergoesa change of length of between about 0.00025% and 0.000375%.
 11. Theimplant of claim 1, wherein one or more of the planar truss unitscomprise one or more planar triangular truss units having threesubstantially straight struts and three nodes in a triangularconfiguration.
 12. The implant of claim 1, wherein one or more of theplanar truss units comprises a first planar triangular truss unitcoupled to a second planar triangular truss unit, wherein the first andsecond planar triangular truss units are coupled in an opposing mannerwith a single node defining the apex of each planar triangular trussunit.
 13. The implant of claim 1, wherein a diameter of the struts ofthe web structure are predetermined such that when the web structure isin contact with the bone at least a portion of the struts create amicrostrain in adhered osteoblasts, bone matrix, or lamellar tissue. 14.The implant of claim 1, wherein a length of the struts of the webstructure are predetermined such that when the web structure is incontact with the bone at least a portion of the struts create amicrostrain in adhered osteoblasts, bone matrix, or lamellar tissue. 15.The implant of claim 1, wherein a density of the web structure ispredetermined such that when the web structure is in contact with thebone at least a portion of the struts create a microstrain in adheredosteoblasts, bone matrix, or lamellar tissue.
 16. A method of repairinga bone structure, comprising: obtaining an implant, the implantcomprising: a web structure comprising a plurality of struts joined atnodes to form a space truss comprising a plurality of planar trussunits, wherein the web structure is configured to interface with bonetissue, and wherein the plurality of planar truss units are coupled toone another such that one or more planar truss units lie in a plane thatis not substantially parallel to a plane of a planar truss unit thatshares at least one strut with the one or more planar truss units;wherein a diameter and/or length of the struts and/or density of the webstructure are predetermined such that when the web structure is incontact with the bone at least a portion of the struts create amicrostrain in adhered osteoblasts, bone matrix, or lamellar tissue; andwherein one or more angles defined by two struts and a node of one ormore of the planar truss units are different than one or morecorresponding angles defined by two struts and a node of one or moreother planar truss units, wherein connecting exterior surface strutscouple the nodes of the non-equivalent angle planar truss units to eachother such that the implant has a varied height; and coupling theimplant to the bone structure.
 17. The method of claim 16, wherein thediameter and/or length of the struts and/or density of the web structureis predetermined so that at least a portion of the struts create amicrostrain in the adhered osteoblasts, bone matrix, or lamellar tissueof between about 1με and about 5000με.
 18. The method of claim 16,wherein the diameter and/or length and/or density of the web structureof the struts is predetermined so that at least a portion of the strutscreate a change in length of adhered osteoblasts of between about 0.05%and about 0.2%.
 19. The method of claim 16, wherein the diameter of thestrut is predetermined such that the strut undergoes a change of lengthof between about 0.000125% and 0.0005%.
 20. The method of claim 16,wherein one or more of the planar truss units comprise one or moreplanar triangular truss units having three substantially straight strutsand three nodes in a triangular configuration.
 21. The method of claim16, wherein one or more of the planar truss units comprises a firstplanar triangular truss unit coupled to a second planar triangular trussunit, wherein the first and second planar triangular truss units arecoupled in an opposing manner with a single node defining the apex ofeach planar triangular truss unit.
 22. The method of claim 16, wherein adiameter of the struts of the web structure are predetermined such thatwhen the web structure is in contact with the bone at least a portion ofthe struts create a microstrain in adhered osteoblasts, bone matrix, orlamellar tissue.
 23. The method of claim 16, wherein a length of thestruts of the web structure are predetermined such that when the webstructure is in contact with the bone at least a portion of the strutscreate a microstrain in adhered osteoblasts, bone matrix, or lamellartissue.
 24. The method of claim 16, wherein a density of the webstructure is predetermined such that when the web structure is incontact with the bone at least a portion of the struts create amicrostrain in adhered osteoblasts, bone matrix, or lamellar tissue.